Turn a rotary dial phone into an mp3 mixtape, with each number corresponding to one track, except for 8, which plays a random track (Magic 8-Ball). When the phone is on cradle, dialing a number sets the volume. Thanks to simonjenny, of the Fairytale Phone project, (https://gist.github.com/simonjenny/8d6c29db8b8a995a4d89) for the basic approach.

mixPhone.py

#!/usr/bin/python3
import RPi.GPIO as GPIO  
import math, sys, os
import subprocess
import socket
import glob

#Global setting to control whether random play plays on.

#Set GPIO Pin Behavior
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)  

#24 goes to GREEN
GPIO.setup(24, GPIO.IN, pull_up_down=GPIO.PUD_UP)
#27 Goes to YELLOW - Cradle Status
GPIO.setup(27, GPIO.IN, pull_up_down=GPIO.PUD_UP)

#5 Goes to ORANGE
#Needs New Pin umber to not conflict with Adafruit Sound Bonnet
GPIO.setup(5, GPIO.IN, pull_up_down=GPIO.PUD_UP) 


#Open a Devnull Stream to send unwanted output
DEVNULL = open(os.devnull, "w")

#My sound files are in /media/mp3s.  in /media, I have softlinks to the 
#Top 9 tracks in /media/mp3s.  #8 is reserved for a random track from the 
#full collection.  For example, if I want SotrmyMonday.mp3 to play when 
#I dial a 5, 
#	 ln -s /media/mp3s/StormyMonday.mp3 5.mp3



# The next three lines count the number of available mp3s and print 
# an informative message.  They are not otherwise necessary, and can 
# be commented out.
import fnmatch
mp3Count = len(fnmatch.filter(os.listdir("/media/mp3s"), '*.mp3'))
print(str(mp3Count) + " files are available.\n\n")


c=0
last = 1


#initialize volume
volArg ="-g 65"

isOffHook = 0

def count(pin):
	global c 
	c = c + 1
sys.stderr.write("A Cradle Active - isOffHook = "+ str(isOffHook)+"\n")


GPIO.add_event_detect(27, GPIO.BOTH)

def checkCradle():
	global isOffHook
	
	newIsOffHook = GPIO.input(27)	
#	sys.stderr.write("B Cradle Active  - newIsOffHook = "+ str(newIsOffHook)+"\n")
	if isOffHook != newIsOffHook:
		sys.stderr.write("C Cradle Active\n  GPIO.input(27): = "+ str(GPIO.input(27)) +"\n")

		if GPIO.input(27)==0:
			isOffHook = 0
#			sys.stderr.write("D Cradle Active\n  GPIO.input(27): = "+ str(GPIO.input(27)) +"\n")
			sys.stderr.write("Hanging up\n\n\n")
			try:
				player.kill()  #Stops currently playing song (if applicable)
			except NameError:
				pass
		else: 
			isOffHook = 1
#			sys.stderr.write("Ec  Cradle Active\n  GPIO.input(27): = "+ str(GPIO.input(27)) +"\n")
			sys.stderr.write("Picking up\n\n\n")



GPIO.add_event_detect(5, GPIO.BOTH)

while True:
	try:
		checkCradle()  # Get cradle status	
		
		if GPIO.event_detected(5): #Dialing any number
			checkCradle()  # Get cradle status		
			current = GPIO.input(5) 
			if(last != current):
				if(current == 0):
					GPIO.add_event_detect(24, GPIO.BOTH, callback=count, bouncetime=10)
				else:
					GPIO.remove_event_detect(24)
					number = math.floor(c/2)
					sys.stderr.write("c = "+ str(c)+ "\n")
					sys.stderr.write("number = "+ str(number)+ "\n")
					if isOffHook == 0:	
						volume = number*10
						volArg = "-g "+ str(volume)
						sys.stderr.write("changing volume to "+ str(volume)+ "%\n\n\n")	
						
	
					else:
						try:
							player.kill()  #Stops currently playing song (if applicable)
						except NameError:
							pass
							
						filename = "/media/"+str(number)+".mp3"

						if number == 8: # If I dial an 8, play the whole directory randomly
								player = subprocess.Popen(["mpg123", "-K","-Bz", "/media/mp3s/" ,volArg ], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
						else:
							print("filename = "+ filename)
							sys.stderr.write(filename+"\n\n\n")
							player = subprocess.Popen(["mpg123",  filename,"-K", "-q", volArg], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
					
					c=0
				last = GPIO.input(5)
	except KeyboardInterrupt:
		break